Servicing
Diaphragm Vacuum Pump N 828 / N 838
48
Translation of original Operating and Installation Instructions, english, KNF 121249-121517 09/19
Fig. 32: Pump head N 838 KN_-versions (pump head made of plastic)
a.) Preparatory steps
1. Remove the pumps from the source of electrical power. Make
sure the pump is voltage-free and secure it.
2. Only for models with DC motors (no cooling fan) and for pump
N 838.1.2 KNE: Remove cover (
1
) from pump housing after
loosening the four screws.
On these models, which have no fan, where reference is made
to turning or holding the cooling fan, the necessary operations
must be carried out by turning or holding the counterweight.
b.) Remove pump head
1. Mark the position of the head plate (
3
), intermediate plate (
2
)
and housing (
5
) relative to each other by a drawing line with a
felt-tip marker (
M
, see Fig. 31). This helps avoid incorrect as-
sembly later.
2. Undo the 4 screws (
4
) in the head plate (
3
) and lift the head
plate with the intermediate plate off the pump housing.
For two-headed pumps:
Undo the head-plate screws (
4
) in the head plate (
3
) and lift
the two head-plates with the intermediate plates (
2
) and the
pneumatic connections (
13
) off the pump housing.
Fig. 31: Two-headed pump
(N 838.1.2 KNE)
Legend
1
Cover
2
Intermediate plate
3
Head plate
4
Screw
5
Housing
6
Valve plate/sealing
7
Structured diaphragm
8
Diaphragm spacer
9
Screw
11
Disk spring
12
Washer
13
Pneumatic connection
M
Marking